Gold alloy



Patented Jan. 31, 1933 UNITED STATES PATENT OFFICE- LOUIS LENFANT, OF PARIS, FRANCE, ASSIGNOR TO CABTI ER, SOCIETE ANONYME; OF PARIS, FRANCE, A COMPANY OF FRANCE GOLD ALLOY No Drawing. Application filed July 19, 1930, Serial No. 469,285, and in France June 14, 1930.

My invention has for its object an alloy containing, besides gold in the normal proportion of 750/1000 and other metals such as silver and copper, a certain quantity of chromium.

Owing to this addition of chromium, this alloy possesses quite remarkable qualities which make its use particularly advantageous in jewelry.

In particular, this alloy is harder than the ordinary commercial metals or alloys, so that it can be used in thinner form. Furthermore, the presence of copper gives the alloy a redder, warmer shade than that of ordinary white gold. Lastly, this alloy does not harden when hammered or drawn in the cold state and it can be rolled to one tenth of its original thickness without annealing, which is very important for jewelry. Of course it is perfectly ductile and can easily be stamped. By way of example optimum limits for the proportion of chromium can be indicated as ranging from 0.001 to 0.025. The alloy would then have the following com 'osition:

gold: 750 per thousand, chromium: mm 1 to 25 per thousand, silver and copper: the remainder.

As a result of my experiments I have found out that the percentage of cop er should 0 preferably be higher than that 0 silver, the

proportion being, for instance:

quantity of copper 14 quantity of silver but it should be well understood that this indication is not limitative.

What I claim is A gold alloy intended for jewelry having the following composition:

Gold f f l? Copper 14 Silver 10 Chromium 1 In testimony whereof I have signed this 

